Oscillating chain stitch looper



April 10, 1962 Filed July 18, 1960 KATSUYASU O-OCHO OSCILLATING CHAIN STITCH LOOPER 4 Sheets-Sheet 1 KATSUY/ISU HIVIVTOR 0-0c H0 April 1962 KATSUYASU O-OCHO 3,028,823

OSCILLATING CHAIN STITCH LOOPER Filed July 18, 1960 4 Sheets-Sheet 2 m EA/raR April 10, 1962 KATSUYASU O-OCHO 3,028,823

OSCILLATING CHAIN STITCH LOOPER Filed July 18, 1960 4 Sheets-Sheet 5 'WVENroR K19 TS Y/v'Sl/ O-O H p 1962 KATSUYASU oocHo 3,028,823

OSCILLATING CHAIN STITCH LOOPER Filed July 18, 1960 4 Sheets-Sheet 4 -INVEN7'0R m1" suynsu o-ocno MM WW, M y:-

United States Patent @fifice 3,028,823 Patented Apr. 10, 1962 3,028,823 OSCILLATING CHAIN STITCH LOOPER Katsuyasu O-ocho, 51 Ebisu-cho, Hiroshima City, Japan Filed July 18, 1960, Ser. No. 43,621 2 Claims. (Cl. 112199) This invention relates to chain stitch apparatus in conventional lock stitch sewing machines and its object is to provide a new chain stitch apparatus and means for optionally performing either conventional lock stitch or chain stitch.

With this object in view, the present invention provides a chain stitch apparatus in which a chain stitch shuttle having a hook adapted to take a thread at the back of the needle, a recess formed under the hook and a forwardly inclined helical projection provided with a threadtaking edge adapted to form a thread loop thereon, is fitted in a shuttle race.

According to the present invention, chain stitch can be performed with an upper thread alone by merely replacing a conventional lock stitch shuttle by a chain stitch one, and besides the structure of the device is very simple.

Other and the further objects of the present invention will become apparent from the following specification and claims taken together with the accompanying drawings in which is shown the preferred embodiment of the chain stitch apparatus in a conventional lock stitch sewing machine according to the present invention.

FIG. 1 is an elevation view of a part of a sewing ma.- chine embodying the present invention.

FIG. 2 is a front-side perspective view of a chain stitch shuttle according to the present invention.

FIG. 3 is a back-side perspective view of the same.

FIGS. 4 to 15 show the process of the chain stitch according to the present invention.

In these drawings reference numeral 11 indicates a chain stitch shuttle fitted in a shuttle race 12 of a conventional lock stitch sewing machine. The shuttle 11 is pro vided with a semi-annular wall 13 having a hook 14 at its upper end, adapted to revolve driven by a shuttle driver 15, and a recess 16 is formed under the hook 14. On the shuttle 11 is formed by punching an inclined helical projection 17, having a nail 18 at its end, a thread-taking edge 19 at the bottom and an arc-shaped edge 20 at its outer side. A thread stopper 21 is formed at the upper end of an opening 22 and a gap 23 is formed between the hook 14 and the nail 18. Along a straight edge 24 of a fiat base 25 of the shuttle 11 is formed a backward bent portion 26 to prevent the thread slipping out in its maximum tention, and a bridge 27 goes arc-shaped between the middle part of the wall 13 and the bottom of the bent portion 26 to keep the thread from falling into a groove in the shuttle race 12.

In FIG. 4 the needle 28 is at its lowest point with a thread 29, having pierced cloth 3t and a board 31. Then, a little after the needle 28 begins to rise, the shuttle 11 starts revolving in the direction of the arrow, the hook 14 taking the thread 29 at the back of the needle 28. FIG. shows the state in which the shuttle 11 has revolved nearly 100 degrees and the thread 29 is caught at the recess 16 engirdling the shuttle 11. FIG. 6 shows the finish of the forward revolution of the shuttle 11, in which a beam 32 (shown in FIG. 1) being in process of rising upward, the thread 29 is tightly strained, caught at the recess 16, the projection 26 and the bridge 27, and in this way it is kept from siipping off the shuttle 11 or getting in the groove of the shuttle race 12 or the gap between the shuttle 11 and the driver 15. FIG. 7 shows the reverse side of FIG. 6. In FIG. 8 the shuttle 11 begins to revolve backward in the direction of the arrow and the thread 29 holds tight enough, as the cloth 30 is fed one stitch ahead and the beam 32 is still in rising. In FIG. 9 the thread 29 forms a loop 29 caught on the thread-taking edge 19 and the arc-shaped edge 20, while the needle 28 comes down through the cloth 30 and the board 31 into the gap 23. In FIG. 10 the shuttle 11 has finished its backward revolution and the needle 28 is completely got into the thread loop 29 which is separated from the needle 28 not to be tangled with the thread 29: newly coming down. Then the shuttle 11 begins the forward revolution again, and the newly-coming thread 29 taken by the hook 14 and the recess 16, as shown in FIG. 11, passes the thread loop 29, which is on the point of gradually slipping off the thread-taking edge 19 and the arc-shaped edge 20. In FIG. 12 the thread loop 29 is completely off the thread-taking edge 20 and the stopper 2i, and though the recess 16is still drawing on the thread 29 the thread loop 29, never changes in size, for the beam 32 is in process of descent and the thread 29 is kept rather loose. FIG. 13 again shows the finish of the forward revolution of the shuttle 11, in which the beam 32 is already in rising process and the thread loop 29 is gradually narrowed, the thread 29 strained. In FIG. 14 the beam 32 rises on and one chain stitch is formed, the more tightly owing to the progress of the cloth 30. In FIG. 15 the shuttle 11 is turning on backward, giving another thread loop. And by thus repeating this process, =cha-in stitches are got in succession.

It is thought that the invention and its advantages will be understood from the foregoing description and it is apparent that various changes may be made in the forms, construction and arrangement of the parts without departing from the spirit and scope of the invention, the form hereinbefore described and illustrated in the drawing being merely a preferred embodiment thereof.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is:

l. A looper for use in a sewing machine having a bobbin shaft rotatable first in one direction from a starting position for more than and less than 360 and then in the other direction to the starting position, said looper comprising a semicircular wall member lying in a flat plane, a hook at one end of said wall member projecting in a circular direction from the end of the wall member, a flat base member extending across the open side of said semicircular wall member and adjoining the ends of said wall member, said flat base member having a recess therein immediately beneath said hook and extending in the opposite direction from the direction in which said hook projects, a laterally extending flat plate on the edge of said flat base member which lies between the ends of said wall member, said flat plate terminating short of said recess, said plate extending laterally in only one direction from the plane in which said semicircular wall lies, a helical thread spreading member extending from a point adjacent the center of the flat base member first toward the other end of said semicircular wall member and the curving around toward said wall member and extending substantially parallel thereto and with a slightly smaller radius and projecting beyond the end of said hook, said helical member also extending laterally of the plane in which said wall member lies in a direction opposite the direction in which the fiat plate extends and in an amount gradually increasing from the start to the projecting end of said helical member, and a thread stopping member connected between the outer edge of said helical member and said wall member substantially midway of the length of said helical member to provide a curved free edge on said helical member between the start of said helical memher and said thread stopping member.

2. A looper for use in a sewing machine having a bobbin shaft rotatable first in one direction from a starting position for more than 180 and less than 360 and then in the other direction to the starting position, said looper comprising a semicircular wall member lying in a flat plane, a hook at one end of said wall member, a base member mounted within said semicircular wall member, a laterally extending plate on said fiat base member extending the ends of said semicircular wall member and extending laterally only in one direction from the plane in which said semicircular wall member lies, a helical thread spreading member extending from a point adjacent the center of the flat base member first toward the other end of said semicircular wall member and then curving around toward said wall member and extending substantially parallel thereto and with a slightly smaller radius and projecting beyond the end of said hook, said helical member also extending laterally of the plane in which said wall member lies in a direction opposite the direction in which the fiat plate extends and in an amount gradually increasing from the start to the projecting end of said helical member, and a thread stopping member connected between the outer edge of said helical member and said wall member substantially midway of the length of said helical member to provide a curved free edge on said heli cal member between the start of said helical member and said thread stopping member.

References Cited in the file of this patent UNITED STATES PATENTS 

